The world market is increasingly demanding tobaccos with well defined characteristics. Health reasons provide the main incentive for the production of cultivars with low nicotine, the main alkaloid of tobacco, and with low tar content. For the Roumanian tobacco cultivars, the average content of nicotine is lower than 3% of the weight in the dry substance. Specifically, the current values for the main tobacco types are: Oriental 1.0 - 1.5%, Virginia 1.5 - 2.0%, Burley 1.5 - 3.0. The biosynthesis of nicotine is under polygenic control but is almost equally influenced by agro-ecological conditions. Low and high nicotine varieties have been crossed in diallelic fashion to study the hereditary transmission. The F1 and F2 hybrids have been analyzed for their content in nicotine. A computer model of the hereditary transmission of genetic characters under polygenic control has been developed. The quantitative data for the nicotine content of Roumanian tobacco types have been used as a study case. The program can be used for the improvement of the tobacco quality by computer-aided selection. Predictions on the number of generations necessary to achieve the user-imposed characteristics are also provided by the software. The program is implemented in ANSI standard C language to be portable on any platform. Friendly graphic user interfaces are provided for the Windows environment.